Improvement in feed-wheel-operating mechanisms



H. A. M. HARRIS.

Feed-Wheel Operating Mechanism.

Patented July 16, 1872. E91

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UNITED STATES 'PATENT OFFICE.

HARMAN A. M. HARRIS, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO HIMSELFAND THOMAS E. GLENN, OF SAME PLACE.

IMPROVEMENT IN FEED-WHEEL-OPERATING MECHANISMS.

Specification forming part of Letters Patent No. 129,131, dated July 16,1872.

To all whom it may concern:

Be it known that I, HARMAN A. M. HAR- RIS, of the city and county ofPhiladelphia and State of Pennsylvania, have invented certain new anduseful Improvements in Feed- Mechanism for Sewing-Machines, of which thefollowing is a specification:

My improvements relate to the class of feed mechanism termedfeeds-wheel, in which a serrated-edged wheel having an intermittentrotary motion feeds the fabric to the needle; and the object of myinvention is to provide an improved friction-clutch for rotatin g thefeed-wheel, as well as to afford means for compensating wear of theclutch.

In the accompanying drawing, Figure 1 is a view, partly in elevation andpartly in section, of a feed-Wheel with my improvements attached; Fig.2, a section through the same at the line :0 a: of Fig. 1; Fig. 3, aview in perspective of a friction-clutch detached; and Fig. 4, a similarview of the compensating-lever.

The feed-wheel A has a serrated rim, a which feeds the fabric to theneedle, and a hollow boss or hub, a through which a spindle, A, securedto the table B in proper relation to the cloth-bed'U, passes, thefeedwheel being loose upon the spindle A. A center block, D, providedwith a lever-arm, D, and toe d, is journaled upon the hub a*. Thelever-arm is operated by a cam, E, on a shaft, E, properly connectedwith the driv-.

ing mechanism of the machine, and is retracted after each stitch by thespring (1 The frictionclutches F, which transmit motion from thelever-arm to the feedwheel, bear against the edges of notches d in thecenter block D, and are provided with jaws, which embrace a flange, a onthe feed-wheel. Springs f, attached to hooks f on the center block D,serve to keep the clutches F in close contact with the flange a andcarry them around with the lever-arm when it is retracted by the spring(1 during which period the wheel re mains stationary.

As heretofore constructed a slot has been cut in the clutch, so as toform a jaw, substantially straight, or curved ,in correspondence withthe rim a. This form of jaw operates successfully when new, but as itssurfaces wear by use the slot becomes Wider, and the clutch slips uponthe flange and fails to carry the wheel round with the lever-arm; Myimproved clutch is constructed with a circular recess, f, the center ofwhich coincides with the center line of the flange a, and a slot, ftransverse to the circular recess f and wide enough to fit easily uponthe flange 01. The wearing surfaces are thus formed at the oppositecorners of the intersection of the recess and the slot, and as theclutch wears along the side of the recess the sides of the jaw remainequivalent, and it continues to clamp the flange of the wheel withouttendency to slip thereon. A jaw thus formed, moreover, gripes the flangemore firmly than if provided with single bearing-surfaces-only.

The friction-clutches when new are set with a limited'amount of lead oradvance of the radius which passes through their rear ends, and will beavailable until worn about a corresponding distance in rear thereof.

In order to utilize the entire circular jaw and compensate for wearthereon, I provide a compensating-lever, G. When the compensating-'lever is employed its toe G bears against the edge of the notch d ofthe center block D, and the clutch F is formed with a threaded stem, f,concentric with the recess f and is secured to the compensating-lever bya nut, f its free end resting in one of a series of grooves, g, formedin the compensating-lever. As the clutch wears the nut may beslackenedand the clutch moved back into another groove, therebycorrespondingly varying its inclination with a radial line, andcompensating for the wear upon the circular jaw. By this means the wholesurface of the jaw may be made available and the durability of theclutch consequently increased.

To prevent displacement of the clutches from the flange I provide aplate, H, which rests upon the spindle A, and is held up against theclutches by the spring h, which serves to maintain the parts in properrelation without excessive friction.

I claim as my invention-- 1. The combination, with a feed-wheel for Intestimony whereof I have hereunto'sub sewing-machines, of afriction-clutch, the jaws scribed my name. o

of which are formed with a circular recess and ,H. A. M. HARRIS. atransverse slot, substantially as set forth.

2. The combination, with a feed-wheel for Witnesses: sewing-machines, ofa friction-clutch and com- J. SNOWDEN BELL, pensating-lever,substantially as set forth. J NO. H. HOGAN.

